Safety device for drilling derricks



June 19; 1951 G. E. KEMNITZ 2,557,543

SAFETY DEVICE FOR DRILLING DERRICKS Filed March 10, 1950 2 Sheets-Sheet1 INVENTOR. GEORGE E. KEMNITZ BYK WN /W ATTORNEYS G. E. KEMNITZ SAFETYDEVICE FOR June 19, 1951 DRILLING DERRICKS 2 Sheets-Shet 2 Filed March10, 1950 INVENTOR.

Patented June 19, 1951 SAFETY DEVICE FOR DRILLING DERRICKS George E.Kemnitz, Tulsa, Okla., assignor to Noble Drilling Corp., Tulsa, Okla., acorporation of Delaware Applic'ation March 10, 1950, Serial N 0. 148,906

11 Claims.

The present invention relates to drilling derricks or masts, and moreparticularly to safety means capable of attachment to the legs ofconventional drilling derricks or masts to prevent Fig. '7 is a brokensection taken along line l--1 of Fig. 5 and also viewed in the directionof the arrows.

Referring to the drawing, the drilling derrick injury to members of adrilling crewby a joint of 5 or mast I0. is positioned above the rotarytable I I drill pipe or casing falling while it is bein hoisted locatedat the center of the derrick floor l2. At above the derrick floor fromthe pipe rack. one side of the derrick floor [2 is the conventional Inoil well drilling or similar'drilling operations, draw works [3 fromwhich the drilling line M the derrick is positioned above the rotarytable runs up through the crown block (not shown) located at the centerof the floor and pipe lengths 19' and to traveling blocks (not shown)supporting are hoisted above the level of the fioor through the hook(not shown) and elevators. At one end a door frame in the derrick ortower from a of the draw works is a winch or cathead I5. 0p rack outsidethe derrick and below the level of the: posite the draw works on theopposite side of the derrick floor, being pulled up a ramp duringderrick or tower I0 is the entrance frame or V- hoisting. Frequentlyduring hoisting the hoisting door It through which additional drill pipeor cable will break while the pipe lengths are suscasing lengths ll arebrought and hoisted above pended therefrom and permit them to fall ontothe floor 12 as needed. The pipe or casing lengths the floor and injureor kill members of the drill I? are usually racked outside the derrickon a crew on the floor. Principal objects and features lower level thanthe derrick floor l2 and are of this invention are the provision ofsimple safepulled up a ramp or walkway is by attaching a ty means orsafeguards designed to prevent-such sling line lg to the Section lengthH to injuries or death by trapping the pipe lengths in moved from therack to a position above the-floor their fall on breakage of thehoisting line and I2; The sling line i9 is run through the crownprecluding their falling to the floor of the derblock (not shown) andthe other end is wound rick. around the winch or cathead l5 which ismoti- Further principal objects and features of the vated'by the drawworksl3. Sometimes the sling invention are the provision of. safetymeans of e 9 W b as e p pe length I7 s being the character describedthat are simple in conhoisted above the derrick floor l2 as describedstruction, relatively inexpensive and capable of and the pipe lengthwill fall or drop to, the derbeing installed on existingstructureswithout any ric floor W ere t may Strike d S e y materialmodification of the latter. lure-or kill a member 01 the drilling crew.

Other objects and novel features will become e'safety means e y th vetion has apparent from the following specification and as its P p l bjet t Provision Of a r ppin accompanying drawings, wherein similar referar a eme t at Will absolutely p a y ence characters denote correspondingparts and 5 i ju y t drill OreW in the event of b a wherein: of a slingline during the hoisting operations Fig. l is a vertical elevation,partially in sec-- just described. To this end, one bracket 29 of a tionof a conventional drilling. derrick equipped. p of brackets av ng ahooked-flange 283a is sewiththe safety means of the invention; Cured y aClamp plate la d bolts 22 a d uts- Fig. 2 is a transverse section takenalong line 23 to one of the frame legs 25 of the frame or 2-2 of Fig, 1and viewed inthe dir tio of the V-door I6 adjacent its lower end; Asimilar arrows; bracket 28 is similarly secured to the other frame Fig.3 is an elevational' view of the derrick of. leg' 25 of the frameor'V-door i6: Each bracket Fig; l viewed from the right of Fig. I and:show- 0- has' a pivot Shaft 25 fixed to and extending: ing one positionof the drill pipe being. hoisted; a rally r f a d utwa d y of th v-doonabove the derrick floor; A lever arm 21. is rotatively supported oneachFig. 4 is a similar elevational view showing arrshaft 26 being. locatedand held in place rotative-r other position of the drill pipe beinghoisted and 1y thereon by washers 2'8, 29" and a cotter pin 30. I inrelationship to the safety means; Each leverZ-l fits telescopically inone end of a Fig. 5 is an enlarged fragmentary elevation tubulararm 3i.The latter is secured to the illustrating detailsof construction of thesafety lever on which it fits by a Collar 32 and cross'boltmeans; 33.The two arms 3| are oppositely directed.

Fig. 6 is a transverse section taken along line toward each other andtheir adjacent outer ends 6-6 of Fig; 5 and viewed in thedirectionof the3M. are preferably closed by plugs 34 whose arrowsyand meeting outersurfaces are angularly shaped in,

complementary manner so that the two angular surfaces of the plugs meetand permit the two adjacent ends of arms 3| to form a substantiallyclosed inverted V in their lowermost positions. A cable securing sleeve35 carrying a cable securing loop 36 is mounted on each pipe 3|. A cablecoupler 31 is secured to each loop 36 and a cable of wire-or rope 38 inturn has one end secured to each coupler 31. The other ends of cables 38are each secured to a coupler 39 and each latter coupler is secured to afixed ring 40, each ring 4|), in turn, being fixedly mounted to one ofthe frame legs 25 of the frame or V-door 6 above the clamp plate 2| onthat leg. The two cables 38 serve to limit downward rotation of the twoarms 3| to their lowermost positions shown in Figs. 3, 4 and 5, whereintheir ends meet without, however, interfering with upward rotation ofthe two arms on their pivot shafts 26.

These two arms 3| supported as described in the frame or V-door l5 andtheir cables 38 provide a very effective safety means for drill crewmembers on the floor I2 of the derrick. As the winch I5 is operated todraw sling line H! in a hoisting direction of a pipe length H, thelatter is drawn up the ramp I8 and through the frame or V- door I 6. Inthe hoisting travel of the pipe length |l, its surface engages theundersides of arms 3| adjacent the outer ends 3|a and pivots each armabout its shaft 26 to permit separation of the ends 3|a sufiiciently forthe pipe length I! to pass between the separated ends to the upper sideof pipes 3| whereupon the latterimmediately fall by gravity to theircable limited lowermost positions, closing the gap between adjacent ends3|a of the arms. This occurs early in the hoisting operation. Anysubsequent breaking of the sling line during hoisting of the pipe lengthN, since the latter is at an angle to the vertical, simply allows thepipe length to fall onto the top sides of the arms 3| or cables 38.These arms 3| or cables 38 thus form a trap, blocking a fall of the pipelength N onto the floor of derrick l2 because of their described returnto meeting position immediately after pipe is drawn through the gapbetween the arms and thereby protect the drilling'crew below on thederrick floor l2 against injury or death.

The arrangement while very simple in practice has proved very effectivein the field as a crew safety device. Its ready installation on existingstructures adds greatly to its commercial utility and, when installed,reduces one of the causes of large accident rates in drillingoperations.

While a specific embodiment of the invention has been described andshown, variations in structural detail within the scope of the claims ispossible and is contemplated. There is no intention, therefore, oflimitation to the exact details shown and described.

What is claimed is:

1. In a drilling derrick having an entrance frame and means for hoistinga pipe length through the frame and above the floor of the derrick,safety means comprising a pair of oppositely directed arms eachpivotally supported at one of its ends at opposite sides of the frameand normally having their free ends meeting, means for preventingpivotal movement downwardly of the two arms substantially below themeeting position of their free ends while permitting upward pivotalmovement of the arms to provide temporary separation of the free endsthereof during passage in upward direction therebetween of a pipe lengthbeing hoisted, said arms being free to return under the influence ofgravity to meeting relationship of their said free ends therebyproviding a trap above the derrick floor to prevent the length of pipebeing hoisted from falling onto the floor.

2. In hoisting apparatus for lifting pipe lengths through an entranceframe and over a floor, safety means comprising a pair of oppositelydirected arms each pivotally supported at one of its ends at oppositesides of the frame and normally having their free ends meeting, meansfor preventing pivotal movement downwardly of the two arms substantiallybelow the meeting position of their free' ends while permitting upwardpivotal movement of the arms to provide temporary separation of the freeends thereof during passage in upwarddirection therebetween of a pipelength being hoisted, said arms being free to return under the influenceof gravity to meeting relationship of their said free ends therebyproviding a trap above the derrick floor to prevent the length of pipebeing hoisted from falling onto the floor.

3. The safety means of claim 2, wherein brackets are secured to theframe, each bracket having a pivot stud, and wherein levers arerotatively mounted one on each pivot stud and wherein the arms fittelescopically one on each lever and are secured thereto.

4. The safety means of claim 2, wherein brackets and clamp plates forsecuring the brackets to the frame are provided, a pivot stud on eachbracket and levers rotatively mounted one on each pivot stud, whereinthe arms are tubular and fit telescopically one on each lever andwherein means for securing each arm to the lever on which it fits areprovided.

5. The safety means of claim 2, wherein the means for limiting downwardpivotal movement of the two arms includes a cable of determined lengthconnected to each arm and to the frame.

6. Safety means for application to the frame of a drilling derrick,wherein pipe lengths are hoisted through the frame and above the derrickfloor comprising a pair of oppositely directed arms each pivotallysupported at one of its ends at opposite sides of the frame above thefloor and normally having their free ends meeting, means for preventingpivotal movement downwardly of the two arms substantially below themeeting position of their free ends while permitting upward pivotalmovement of the arms to provide temporary separation of the free endsthereof during passage upwardly therebetween of a pipe length beinghoisted, said arms being free to return under the influence of gravityto meeting relationship of their free ends, thereby providing a trapabove the floor to catch and prevent the pipe length being hoisted fromfalling onto the floor.

7. The safety means of claim 6, wherein the arms in the meeting positionof their free ends define a closed substantially inverted V.

8. The safety means of claim 6, wherein the means for limiting downwardpivotal movement of the two arms comprise cables secured both to thearms and to the frame.

9. The safety means of claim 6, wherein each arm is tubular and fitstelescopically on a lever and is secured thereto, brackets secured tothe frame, and pivot studs secured to the brackets, each lever beingpivotally mounted on one of the pivot studs.

10. The safety means of claim 6, wherein each arm is tubular and fltstelescopically on a lever and is secured thereto, brackets secured tothe frame, and pivot studs secured to the brackets,

each lever being pivotally mounted on one of the pivot studs and whereinthe means for limiting downward pivotal movement of the two armscomprise cables secured both to the arms and to the frame, and whereinthe arms in the meeting position of their adjacent ends define a closedsubstantially inverted V.

11. In combination with a drilling derrick having a V-door structure andmeans for hoistinga pipe length through the door and over the floor ofthe derrick, safety means comprising a pair of oppositely directed arms,means for pivotally supporting one end of each arm from one of theopposite sides of the structure forming the V- door, and means forpreventing pivotal movement in a downward direction of at least one ofsaid arms below that position at which the free REFERENCES CITED Thefollowing references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,049,008 Herrick July 28, 19362,184,051 Moise Dec. 19, 1939

